I have a 15 DRW RAM 4x4. My B&W hitch is full forward on the lowest setting. My truck sets "LEVEL" with my RAW of 9,750#. I do have rear air ride to keep the load level. Your RV should put your truck near level.
I strongly advise to keep the hitch FULL FORWARD with the head supports straight side towards the cab.
I have a bit over 6" clearance at the tailgate.
My RV sets at 13' 5" with 3" risers.
Your truck should look like this with RV attached and ready for the road.
I am 55" to top back corner of the bed in pic.